Telescopic side port catheter device with imaging system and method for accessing side branch occlusions

ABSTRACT

A medical device and method are provided for accessing a side branch in an artery utilizing an on-board imaging device. The device includes a catheter having a sidewall, an internal lumen, and a side port formed through the sidewall. A perforating guide wire has a proximal portion within the internal lumen and a distal portion arranged to be movable out of the side port. The guide wire can be delivered through the side port to a side branch artery when the catheter is deployed to a location with the side port aligned with the side branch artery. In one embodiment, the catheter includes an on-board imaging system disposed adjacent the side opening. The imaging system images tissue adjacent the side opening to assist with alignment of the guide wire to enter a side branch and/or cross an occlusion within the side branch.

RELATED APPLICATIONS

This application is a continuation-in-part of U.S. patent application Ser. No. 11/838,297 filed on Aug. 14, 2007, and claims priority of U.S. Provisional Application No. 60/837,900 filed on Aug. 14, 2006. The content of these prior applications are incorporated herein by reference.

BACKGROUND OF THE INVENTION

Field of the Invention

The present invention relates generally to catheters and methods of treating a stenosis of an artery. In particular, the present invention relates to catheters and methods for accessing chronic total occlusions (CTOs) in arteries caused by the buildup of arterial plaque tissue.

Description of the Related Art

Chronic total occlusion (CTO) is a condition where arterial plaque tissue grows to complete stenosis of an artery and prohibits blood flow. A CTO is formed by the agglomeration of three separate physiological materials: (i) cholesterol or fat, (ii) collagen or fibrous matter, and (iii) calcium-based deposits. A CTO is also often referred to as a functional occlusion.

There are two causal pathogenic phenomena often associated with the formation of a CTO. The first is the late development of an acute occlusion. The second is the progressive occlusion of a long-term high degree stenosis. Both involve a pre-existing plaque or thrombus to which the fat and fibrous material adhere, building up until a blockage of the blood vessel occurs. A CTO 10 will sometimes form in a side branch 11 of an artery 12 as shown in FIG. 1, which is difficult to access using conventional catheters and surgical techniques.

Physicians currently attempt to perforate CTOs 10 in side branches 11 using a stiff guide wire 13 as shown in FIG. 2. A small catheter 14 is used to position the guide wire 13 at the occlusion 10.

Another conventional technique involves the use of a curved catheter 15 to align a perforating guide wire 16 with the angle of the side branch 11, as shown in FIG. 3. One of the primary problems with this approach occurs when a compressive force is applied to the guide wire 16. The guide wire 16 must be pushed to perforate the occlusion 10 and as it is pushed, the catheter 15 in which the guide wire 16 is contained reacts in a negative manner, as shown in FIG. 4. As can be seen, the catheter 15 will be pushed and/or rotated away from the side branch 11, or misaligned with the side branch 11, as compressive force is exerted on the guide wire 16. The restraint offered by the catheter 15 is limited because it must be made of a material that is soft enough not to injure the arteries as it is advanced into the vascular system. Catheters are limited as to the amount of stiffness the catheter can contain before it will injure the artery as it is aligned with the side branch. In addition, the curvature of the catheter can cause substantial “whip” as a physician torques the catheter to align it with the side branch.

A compliant balloon 17 can be attached to the catheter 18 to help limit the reaction forces on the catheter 18, as shown in FIG. 5. The balloon 17 is inflated through a separate lumen in the catheter 18. The balloon 17 allows for more stability in the catheter 18 as it is used. However, it still suffers from the cantilever type positioning exhibited in FIG. 4. In addition, it is still subject to whip caused by the curvature of the catheter as torque is applied to position the catheter.

There is a need in the industry for improved devices and methods to assist surgeons in accessing CTOs in side branches of arteries.

SUMMARY

The present disclosure provides an occlusion crossing system utilizing an imaging system carried by the catheter to assist in guiding the advancement of the occlusion penetrating device.

In one aspect, the present disclosure provides a method of crossing an occlusion within a vessel. The method comprises positioning a catheter within a vessel of a patient, the catheter including an imaging element, a steering assembly and an occlusion crossing wire extendible through an exit opening in the catheter. The method includes advancing the imaging element through a main vessel to a position adjacent an occlusion of a side vessel and imaging the occlusion along with a portion of the side vessel. Once the vessel has been imaged, the catheter can be rotated to align the exit opening with the occlusion and the crossing wire can be advanced through the exit opening and into the occlusion. The steering assembly is operable to change the trajectory of the crossing wire.

In still a further form, the present disclosure provides a method of treating an internal structure within a patient. The method includes positioning a catheter adjacent a structure to be treated, the catheter including an imaging element, a steering assembly and a therapy delivery device extendible through an exit opening in the catheter, the steering assembly operable to adjust the trajectory of the therapy delivery device as it extends through the exit opening. The method includes advancing the imaging element to a position adjacent the structure to be treated, imaging the structure to be treated with the imaging element and aligning the exit opening with the structure to be treated. Once the exit opening is properly aligned, the therapy delivery device can be advanced through the exit opening and toward the structure to be treated. In one aspect, the trajectory of the therapy device can be controlled by the steering assembly while advancing the therapy delivery device.

In yet a further feature, the present disclosure provides a vessel occlusion crossing system. The system includes a catheter body having a lumen, an imaging element disposed on a distal portion of the catheter, a crossing wire slidably disposed within at least a portion of the catheter, and a steering assembly for changing the direction of the crossing wire after exit from the catheter body.

These and other aspects of the present disclosure will become apparent from the following detailed description and associated drawings.

BRIEF DESCRIPTION OF THE DRAWINGS

The present invention will become more clearly appreciated as the disclosure of the present invention is made with reference to the accompanying drawings. In the drawings:

FIG. 1 shows a vessel in a coronary vascular system with a side branch that is totally occluded.

FIG. 2 shows a conventional technique used to perforate an occlusion with a stiff guide wire and a small catheter to position the guide wire at the occlusion.

FIG. 3 shows a conventional technique that uses a curved catheter and/or curved catheter/guide wire combination to align the perforating guide wire with the angle of the side branch.

FIG. 4 illustrates the reactive forces on the catheter when the guide wire is pushed to perforate the occlusion using the conventional technique.

FIG. 5 shows a catheter with a balloon attached to help limit the reaction of the catheter as the guide wire is pushed into the occlusion.

FIG. 6 shows a catheter according to an embodiment of the present invention having a side port through a sidewall for delivering a guide wire to a side branch occlusion in an artery.

FIG. 7 shows another embodiment of the present invention in which the catheter contains a single lumen and side port through which the guide wire is passed.

FIG. 8 shows another embodiment of the present invention in which support balloons are used to stabilize the catheter during usage.

FIGS. 9 and 10 show another embodiment of the present invention in which a single support balloon is centered over the side port and attached to the catheter shaft at the proximal and distal ends of the balloon and around the side port.

FIG. 11 shows another embodiment of the present invention in which a “hot dog bun”-shaped balloon is centered about the side port and attached to the catheter shaft.

FIG. 12 shows another embodiment of the present invention in which two lumens are provided in the catheter; one lumen leading to the side port and the other lumen providing a passage for inflating support balloons attached to the catheter.

FIGS. 13 and 14 are side and end views of another embodiment of the present invention in which a channel is provided for inserting the catheter over a guide wire previously placed in the non-occluded artery.

FIGS. 15 and 16 are side and end views of another embodiment of the present invention in which a guide wire lumen is provided on the exterior of the primary catheter with a support balloon.

FIG. 17 shows another embodiment of the present invention in which a guide wire lumen is provided on the exterior of the primary catheter without a support balloon.

FIG. 18 shows another embodiment of the present invention in which no extension of the catheter extends past the side port, and a molded tip is provided to facilitate movement of the exiting guide wire.

FIGS. 19 to 21 show another embodiment of the present invention in which the side port is movable relative to the base catheter to change the angle at which the guide wire exits the catheter.

FIG. 22 shows another embodiment of the present invention in which telescoping sleeves are used to change the angle at which the guide wire exits the catheter.

FIG. 23 shows another embodiment of the present invention in which telescoping inner and outer tubes having offset ports at their distal ends are used to change the angle at which the guide wire exits the catheter.

FIGS. 24 and 25 show the catheter of FIG. 23 with the inner tube at different positions relative to the outer tube to cause the guide wire to exit the catheter at different angles.

FIGS. 26 and 27 show another variation of the catheter of FIG. 23 in which the exit port of the outer telescoping tube is offset from the longitudinal axis of the catheter.

FIG. 28 illustrates a first embodiment of an occlusion crossing system incorporating an imaging system.

FIGS. 29 and 30 illustrate a further embodiment of an occlusion crossing system incorporating an imaging system.

FIGS. 31-33 illustrate still a further embodiment an occlusion crossing system incorporating an imaging system.

FIG. 34 illustrates a display device displaying an image associated with the imaging system.

DETAILED DESCRIPTION OF THE INVENTION

Side port catheters and methods for accessing side branch occlusions in arteries according to the present invention will now be explained in detail with reference to the accompanying drawings.

FIG. 6 shows a catheter 20 having a sidewall 21 and an internal lumen 22. A side port 23 is formed through the sidewall 21 of the catheter 20. A perforating guide wire 24 is provided in the catheter 20 for accessing and treating a side branch occlusion 10 in an artery 12. The guide wire 24 has a proximal portion 25 within the internal lumen 22 of the catheter 20 and a distal portion 26 arranged to be movable out of the side port 23. The side port 23 is arranged to bend the guide wire 24 away from a longitudinal axis of the catheter 20 as the guide wire 24 passes through the side port 23. The guide wire 24 can thus be delivered through the side port 23 to the occlusion 10 in the side branch 11 of the artery 12.

In FIG. 6, a distal portion 27 of the catheter 20 extends for some distance past the side port 23 to add stability to the catheter 20 while the guide wire 24 is being delivered through the side port 23. The perforating guide wire 24 may be either straight or formed with a pre-curved tip at its distal portion 26. If a curved tip guide wire 24 is used, the guide wire 24 will be held straight within the lumen 22 of the catheter 20 until the distal portion 26 of the guide wire 24 exits through the side port 23. The length of the catheter 20 will help stabilize the catheter 20 as the curved guide wire 24 is pushed through the catheter 20. If a straight guide wire is used, the guide wire 24 must be flexible enough to deflect and bend as it enters the curvature contained within the catheter 20 to deflect the guide wire 24 out of the side port 23.

The catheter 20 with the side port 23 shown in FIG. 6 will torque with very little “whip” and allow for relatively easy positioning of the side port 23. The compressive force of the guide wire 24 necessary to deflect it through the side port 23 will result in a tensile loading on the catheter shaft that is fairly easy to restrain.

FIG. 7 shows an embodiment of a catheter 30 in which the catheter contains a single lumen 31 and side port 32 through which the guide wire 33 is passed. The single lumen 31 truncates at its distal end 34 to the side port 32 to guide the guide wire 33 to the opening of the side port 32.

FIG. 8 shows an embodiment of a catheter 40 with a side port 41 in which one or more support balloons 42, 43 are used to stabilize the catheter 40 during delivery of the guide wire 44 through the side port 41. A first balloon 42 can be positioned proximal of the side port 41, and a second balloon 43 can be positioned distal of the side port 41.

FIGS. 9 and 10 show an embodiment of a catheter 50 in which a single support balloon 51 surrounds the catheter 50 adjacent to the side port 52 and has a recess 53 in the support balloon 51 to allow delivery of the guide wire 54 through the side port 52. In this case, the balloon 51 can be centered over the side port 52 and attached to the outer sleeve 55 of the catheter 50 at the proximal and distal ends of the balloon 51 and around the side port 52.

FIG. 11 shows an embodiment of a catheter 60 in which a balloon 61 having a general shape of a hotdog bun is used for stabilizing the catheter 60. In this embodiment, the balloon 61 has an open side 62 for allowing delivery of the guide wire 63 through the side port 64. The balloon 61 can be centered about the side port 64 and attached to the outer sleeve 65 of the catheter 60 as shown.

FIG. 12 shows an embodiment of a catheter 70 in which two lumens 71, 72 are provided in the catheter. The first lumen 71 serves as the lumen for delivering the guide wire to the side port 73, and the second lumen 72 serves as a balloon inflation lumen for delivering gas or fluid to a balloon inflation port 74 for inflating the support balloon or balloons after insertion of the catheter 70 into a patient.

FIGS. 13 and 14 show an embodiment of a catheter 80 in which an insertion lumen 81 is provided for inserting the catheter 80 over a second guide wire 82 previously placed in the non-occluded portion of the artery 12. The second guide wire 82 can pass through the insertion lumen 81 for guiding the catheter 80 into position within a patient's body. As shown in FIG. 13, the insertion lumen 81 is open at both its distal and proximal ends 83, 84 and arranged so that the balloon and the balloon inflation port 85 and the side port 86 of the catheter 80 are located between the distal and proximal ends 83, 84. The insertion lumen 81 passes through the inflation lumen 87 of the catheter 80.

FIGS. 15 and 16 show an embodiment of a catheter 90 in which a tubular member 91 is provided on the exterior of the primary catheter 92. The tubular member 91 provides an insertion lumen for a second guide wire 94 used to guide the catheter 90 into position within a patient's body. In this embodiment, a support balloon 93 surrounds both the tubular member 91 and the primary catheter 92. FIG. 17 shows a similar embodiment of a catheter 95, except that no support balloon is used.

FIG. 18 shows an embodiment of a catheter 100 in which no extension of the catheter extends past the side port 101. In this embodiment, a molded tip 102 is provided to facilitate movement of the exiting perforating guide wire 103.

FIGS. 19 to 21 show another embodiment of a catheter 110 in which the side port 111 is movable relative to the base portion 112 of the catheter 110 to change the angle □ at which the guide wire 113 exits the catheter 110. In this embodiment, the base portion 112 of the catheter 110 has a molded internal guide 114 within its tip 115, and a movable portion 116 in which the side port 111 is formed. The base portion 112 and movable portion 116 are telescoping members that can be adjusted relative to one another. As the side port 111 on the movable portion 116 is positioned relative to the base portion 112, the angle □ of the guide wire 113 exiting the catheter 110 will change. In other words, the movable portion 116 can be moved relative to the base portion 112 to adjust the angle □ of the guide wire 113 exiting the catheter 110. The relative positions of the movable portion 116 and the base portion 112 can be adjusted during a surgical procedure using a push/pull wire or by applying a fluid pressure within a lumen 117 of the base portion 112. Support balloons and the like as described above can be incorporated into this embodiment as desired.

FIG. 22 show an embodiment of a catheter 120 in which telescoping sleeves 121, 122 are used to change the angle □ at which the guide wire 113 exits the side port 111 of the catheter 110. The telescoping sleeves 121, 122 will provide a convenient means by which a surgeon can adjust the relative positions between the outer “movable” portion 121 and the inner “base” portion 122 of the catheter 120 from the proximal end of the catheter 120.

FIGS. 23 to 25 show another embodiment of a catheter 130 in which telescoping inner and outer tubes 131, 132 having offset ports 133, 134 at their distal ends 135, 136 are used to change the angle at which the guide wire 137 exits the catheter 130. The inner and outer tubes 131, 132 are arranged for rotational and/or telescoping movement relative to each other. For example, the inner tube 131 can be moved in a telescoping manner relative to the outer tube 132 from the position shown in FIG. 23 to the position shown in FIG. 24. Further, the inner tube 131 can be moved in a rotational manner relative to the outer tube 132 from the position shown in FIG. 24 to the position shown in FIG. 25.

The inner tube 131 has an internal lumen 138 that leads to the first port 133 at the distal end 135 of the inner tube 131. The outer tube 132 has the second port 134 at the distal end 136 of the outer tube 132. In the embodiment shown in FIGS. 23 to 25, the first port 133 is offset from the longitudinal axis of the catheter 130, and the second port 134 is approximately concentric with the longitudinal axis. In the embodiment shown in FIGS. 26 and 27, both the first and second ports 133, 134 are offset from the longitudinal axis of the catheter. In both embodiments, the first and second ports 133, 134 are offset relative to each other so that relative movement between the inner and outer tubes 131, 132 will cause relative movement between the first and second ports 133, 134 to adjust an angle of the perforating guide wire 137 exiting the catheter.

In the catheter embodiments shown in FIGS. 23 to 27, the degree of deflection of the guide wire 137 can be increased or decreased by telescoping the tubes 131, 132, and/or by rotating one or both tubes 131, 132 to change the alignment of the first and second ports 133, 134. The catheter 130 can also be used in combination with an inflatable stabilizing balloon as described above in connection with the other embodiments disclosed herein.

Catheter devices according to various embodiments of the present invention have been described above. Methods of using these catheter devices to access a side branch 11 of an artery 12 will now be described.

The basic method includes a first step of providing a catheter 20 having a sidewall 21 and an internal lumen 22, a side port 23 formed through the sidewall 21, and a perforating guide wire 24 positioned within the internal lumen 22. A second step is to deploy the catheter 20 to a location with the side port 23 suitably aligned with a side branch 11 of an artery 12 to be accessed. A third step is to move the guide wire 24 through the side port 23 and into the side branch 11 of the artery 12.

In the catheter embodiments having a distal portion 27 that extends past the side port 23, the method will include the step of positioning the distal portion 27 on a distal side of the side branch 11 of the artery 12 to stabilize the catheter 20 while the guide wire 24 is being delivered through the side port 11.

In the catheter embodiments having one or more balloons 42, 43 attached to the catheter, the method may include the further step of inflating the balloon 42, 43 within the artery 12 to stabilize the catheter while the guide wire 44 is being delivered through the side port 41. As described above, a first balloon 42 can be positioned proximal of the side port 41 and a second balloon 43 can be positioned distal of the side port 41.

In the catheter embodiments having an insertion lumen 81, the method may include the further step of guiding the catheter within a patient's body over a second guide wire 82 that passes through the insertion lumen 81. As described above, the insertion lumen 81 has open distal and proximal ends 83, 84 and is arranged so that the side port 86 of the catheter is located between the distal and proximal ends 83, 84.

In the catheter embodiments having a base portion 112 and a movable portion 116 with the side port 111 formed in the movable portion 116, the method may include the further step of moving the movable portion 116 relative to the base portion 112 to adjust an angle □ of the guide wire 113 exiting the catheter.

Referring now to FIG. 28, there is shown an alternative embodiment of a catheter assembly according a further aspect of the present disclosure. The embodiment 200 retains all of the features of FIG. 8 described in detail above, but further includes an on-board imaging system 220. The imaging system is spaced distally by a distance D1 from the sidewall opening 41. In one aspect, D1 can vary from about 1 mm to about 1 cm depending on the desired spacing which may be a function of space constrains within the catheter and the desired imaging angle of the field of view illustrated by dashed lines 230. Typically, the field of view will be oriented between 90 and 45 degrees outwardly from the catheter side wall such that the expected side branch or tissue of interest will be within the primary field of view when deployed within a vessel. As illustrated, a marker element 232 is positioned within the field of view of the imaging system 220 radially aligned about the longitudinal axis to be in alignment with the sidewall opening 41. As shown in more detail with respect to FIGS. 32-34, the marker element 232 provides a visual indication, during imaging, of the orientation of the sidewall opening with respect to surrounding tissue structures and the images viewed on a display screen. Referring now to FIGS. 29 and 30, the catheter system previously described with respect to FIGS. 9-11 has been enhanced to include an on-board imaging system 240. As previously discussed, the system include a visualization marker 242 radially aligned at the some radial or angular location about the longitudinally axis of the catheter, but offset longitudinally, from the side wall opening 64. The imaging systems 220 and 240 may be used to locate the area of interest prior to balloon inflation. Once the area is identified, the balloons of FIG. 28 or the single balloon of FIG. 29 can be inflated to maintain the catheter system in a fixed location allowing the imaging system to monitor the occlusion 10 while deploying the crossing wire. The balloon systems may be particularly useful for optical imaging systems as the blood in the vessel may be displaced by a fluid, such as saline, distal of the balloons for better imaging.

Referring now to FIG. 31, there is shown still a further embodiment of a treating catheter incorporating a steerable crossing wire assembly with an on-board imaging system positioned to aid in the deployment and navigation of the crossing wire as it is extended outside of the delivery catheter. The treating catheter 260 is deployed within the lumen 252 of primary vessel 250. The treating catheter 260 is shown after having been positioned on guide wire 262 by use of the monorail assembly 264. The distal tip 266 containing imaging system 268 has been positioned slightly beyond side branching vessel 290. The imaging system 268 has been used to locate the position of the side branching vessel 290 containing an occlusion 292 and has been oriented such that visual marker 273 is oriented to radially align with the side branching vessel 290. As illustrated, the visual marker is aligned with the side wall opening 270. Thus, the crossing wire 272 can be manipulated by the steering catheter 280 to exit the side wall opening 270 adjacent the side branching vessel 290. As explained more fully above, movement of the steering catheter 280 within the delivery catheter 265 changes the position of the opening 280 with respect to opening 270 such that the crossing wire 272 is effectively guided as it exits the delivery catheter. As shown in FIG. 31, the steering mechanism is moved within the delivery catheter to position the tip 274 of the crossing wire 272 in contact with the surface 294 of the occlusion 92.

Referring now to FIG. 32, there is shown a partial cross sectional diagrammatic view of the treating system 260 incorporating an oscillatory imaging system 268. The oscillatory imaging system 268 utilizes a single transducer 269 that is oscillated through an arc of between 120 and 360 degrees to form an image. Cable 267 provides power to drive the oscillation and carry signals to and from the ultrasound transducer 269. In the illustrated embodiment, the arc defines a field of view FV that is angled backwards toward the opening 270 such that the field of view FV encompasses tissue disposed radially outward from the opening 270. As discussed above, a marker 273 is positioned on the catheter (or within a component of the imaging system) within the field of view such that when the field of view is output on a display device a user can determine the orientation of the marker 273 and aligned opening 270 in relation to the imaged tissue surrounding the catheter.

Referring now to FIG. 33, there is shown still a further embodiment of a treating system 260′ having an alternative imaging system 268′. The crossing wire steering components of the system are the same as set forth above. In the illustrated embodiment, the imaging system 268′ is a 360 degree imaging system that has a field of view that includes all tissue surrounding the catheter in a 360 degree revolution. Exemplary solid-state IVUS systems usable as the imaging system 268′, also referred to as phased-array imaging systems, are described, for example, in U.S. Pat. No. 6,283,920 and U.S. Pat. No. 6,283,921, each of which is incorporated herein by reference in their entirety. Such solid-state systems typically have lower resolution but higher depth of penetration than rotational systems. Although the imaging system may utilize a field of view oriented at 90 degrees from the catheter, as shown in FIG. 33, the exemplary field of view FV′ has been angled rearward at an angle of approximately 45 degrees to define a conical field of view. The field of view FV′ includes a visual marker 273′ aligned with opening 270. In an alternative aspect, the imaging system 268′ could include a single imaging element continuously rotated about an axis.

Referring now to FIG. 34, there is shown an example of a display device 400 showing a display 300 outputting a field of view FV′ from the imaging system 268′. The image 300 illustrates a position of the imaging device at location 305, primary lumen 252 of the vessel at 315, side branching vessel lumen 290 at location 320 and visual marker 273′ at the location designated by arrow 300. As illustrated, the arrow 330 points the direction that the crossing guide wire 272 will be exiting opening 270. Thus, the user can use the visual marker 330 to align the side opening 270 with the branching side vessel 290 as shown in FIG. 34.

As a further feature, the sensed image data received from imaging system 268′ may be further processed by a tissue characterization system. In one feature, the system may identify and display lumen or vessel wall boundaries illustrated by lines 310 on the image 300, along with determining the tissue characteristics of the occlusion 292. In still a further feature, tissue characterization may be used to identify adventitial tissue to alert the user of the location of the adventitial tissue to prevent unwanted penetration outside of the vessel wall. A system and method of adventitial tissue characterization is disclosed in U.S. Patent Application Ser. No. 61/784,570 filed Mar. 14, 2013, entitled: SYSTEM AND METHOD OF ADVENTIAL TISSUE CHARACTERIZATION, incorporated by reference herein in its entirety.

Alternatively, the occlusion crossing guide wire may be replaced with a treatment device such as an ablation electrode or a suturing device. It will be appreciated that with alternative treatment devices steered with the control system described herein as aided by the above described imaging system, that ablation therapies and structural heart repairs maybe accomplished with precision using the combination of mechanical steering control and on-boarding imaging adjacent the treatment device.

The above described imaging systems have been illustrated utilizing an ultrasound imaging system as an example. However, these examples are provided only for the purpose of illustration and the present concepts are not limited to the type of imaging system utilized. Any type of imaging system may be incorporated with the mechanical steering system described above including, for example, but without limitation, optical systems, optical coherence tomography (OCT), photoacoustic sensors, optical IVUS, and spectroscopy.

A specific method of using the treating system 260 will be described below, although any of the treating systems disclosed above can be modified to incorporate an imaging system as described and used in a similar manner. Referring to FIG. 31, as an initial step, a guide wire 262 is positioned in the primary vessel 252 and the treating system 260 is advanced along the guide wire until it is positioned in the area of the occluded side branching vessel 290. As shown in FIG. 34, the imaging system may be moved along the guide wire until the field of view displays an image illustrating a side branching vessel. Once the side branching vessel has been identified, the treating system catheter 260 is rotated until the visual marker 273 (as indicated by the marker 330 on the display) is aligned with the side branching vessel (as indicated by region 320 on the display). Once properly aligned, a user may move the treating device longitudinally along the guide wire to determine the width of the opening of the side branching vessel and its location relative to the distance D1 between the side wall opening 270 and the imaging system 268. Once the opening 270 has been rotationally oriented and longitudinally oriented to be disposed adjacent the side branch 290, the steering catheter 280 is manipulated within the delivery catheter with respect to opening 270 to change the orientation and/or trajectory of the longitudinal axis LA of crossing wire 270 as it exits opening 270. As shown in FIG. 31, the longitudinal axis LA is oriented to extend across the occlusion 292 without penetration side walls of the vessel 290. As described above, the imaging system 268 can be used to identify boundaries of the vessel 290 along with using tissue characterization to determine the tissue type of the material making up the occlusion 292. In this manner, the crossing wire can be safely guided across the occlusion. Once a safe path is identified, the crossing wire 272 can be advanced into and across the occlusion 292. During advancement of the crossing wire 272, the imaging system may be continuously activated so that the position of the crossing wire 272 in relation to the vessel 290 is constantly monitored in real time. The monitoring may include observation of the actual location of the crossing wire as well as a projection of the expected path or trajectory of the crossing wire to avoid inadvertently passing through or otherwise perforating the lumen of the vessel. In some applications, such as subintimal tracking, the imaging system may be utilized to characterize vessel tissue and/or identify borders between vessel wall tissue segments. For example, the imaging system provides display information to the user identifying the boundary of the intima. The user may then use the steering assembly to orient the alignment of the crossing wire to extend along a subintimal path. The process of displaying, identifying and aligning the crossing wire to remain in the subintimal path continues until the crossing wire has been advanced beyond the occlusion. Once beyond, the occlusion as indicated by the imaging system, the steering mechanism can be actuated to cause the crossing wire to change orientations such that further advancement penetrates the intimal tissue and re-enters the lumen of the vessel beyond the occlusion.

In a further aspect, an external imaging system, such as a flurosystem, may be used to image the treating catheter in an image plane that is generally perpendicular to the imaging plane of the imaging system 268. In one aspect, the display 400 includes both an image 300 from the imaging system and an image from the flurosystem. In another aspect, a multi-dimensional model is generated based on inputs from the imaging system 268 and another imaging system and the resulting data is displayed to a user. In this form, the resulting data provided on display 400 may include colorized portions indicating vessel structures, tissues, and the crossing wire. In this form, both the output of the imaging system 268 and the output of the flurosystem may be used to position the treating device, identify a path for crossing the occlusion and monitor progression of the crossing wire as it extends from the delivery catheter.

Although the above method of use has been described in relation to crossing a vessel occlusion, it will be appreciated that the system can used to treat structural tissue defects as well. In one example, the treating system may be guided to a patient's heart. The imaging system 268 is used to image tissue within the heart, such as a valve or a wall, to identify a defect. Once the defect is identified, the treating device is rotated about the longitudinal axis to align the visual indicator with the identified defect. If necessary, the longitudinal position of the opening in the catheter where the treating device exits can be adjusted so the treating device is properly aligned with the tissue to be treated. The treating device can then be steered by the control system to exit the catheter and extend in a direction toward the tissue to be treated. For a heart valve or structural wall defect, the treating system may include a tacking or tissue joining device, such as a T-bar, for joining one tissue structure to another. Alternatively, the treating system may include an ablation device to damage tissue. The imaging system may be utilized to monitor the therapy being delivered in real time. During treatment monitoring, the location of the treatment device may be adjusted by the steering assembly based on image data displayed to the user.

While the invention has been described in connection with specific embodiments thereof, it is to be understood that this is by way of illustration and not of limitation, and the scope of the appended claims should be construed as broadly as the prior art will permit. 

What is claimed is:
 1. A method of crossing an occlusion within a vessel, the method comprising: positioning a catheter within a vessel of a patient, the catheter including: an imaging element, a steering assembly comprising a first tube and a second tube, wherein the first tube is located within the second tube and slides with respect to the second tube, wherein the first and second tubes are telescopically movable with respect to each other, an occlusion crossing wire extending out of an opening in the first tube through a side port in the second tube that provides an exit opening in a side of the catheter, a stabilizing element that provides stability to the catheter located either proximal to or distal to the exit opening, and a visual marker element positioned on the catheter and aligned with the exit opening in the catheter, the visual marker element configured to be within a field of view captured by the imaging element; advancing the imaging element through a main vessel to a position adjacent an occlusion of a side vessel; imaging the occlusion along with a portion of the side vessel; aligning the exit opening in the side of the catheter with the occlusion based on a visual indication of an orientation of the exit opening with respect to the imaged occlusion and the side vessel provided by the visual marker element; changing an orientation of the crossing wire with the steering assembly by moving the second tube telescopically with respect to the first tube, thereby to cause the crossing wire to change its angle with respect to the catheter; and advancing the crossing wire through the opening of the first tube and the exit opening in the side of the catheter and into the occlusion.
 2. The method of claim 1, wherein the imaging includes evaluating tissue characteristics of at least one of the occlusion and the side vessel.
 3. The method of claim 1, wherein the catheter includes the marker detectible by the imaging element, and the aligning further includes rotationally aligning the marker with the side vessel.
 4. The method of claim 1, wherein the imaging includes activating at least one ultrasound transducer.
 5. The method of claim 1, wherein the imaging includes activating an optical coherence tomography sensing system.
 6. The method of claim 1, wherein the steering assembly includes an inner catheter positioned within the catheter, the crossing wire extending within at least a portion of the inner catheter and exiting a distal opening; and further including moving the inner catheter with respect to the exit opening to thereby change the alignment of the crossing wire before advancing the crossing wire through the exit opening.
 7. The method of claim 1, further including imaging the side branch vessel and the crossing wire during the advancing the crossing wire through the exit opening and into the occlusion.
 8. The method of claim 7, further including adjusting the path of the crossing wire utilizing the steering assembly based on the imaging during the advancing of the crossing wire.
 9. A vessel occlusion crossing system comprising: a catheter body having a lumen and a side port that provides an exit opening in a side of the catheter body; an imaging element disposed on a distal portion of the catheter; a crossing wire; a steering assembly comprising a first tube slidably located within the lumen of the catheter body, wherein the first tube is telescopically movable within the lumen of the catheter body, wherein the crossing wire is slidably disposed within the first tube, and wherein the crossing wires are configured to extend to the side port in the side of the catheter body, the steering assembly configured to change a direction of the crossing wire after exit through the side port by moving the first tube telescopically with respect to the lumen of the catheter body thereby to cause the crossing wire to change its angle with respect to the catheter body; a stabilizing element that provides stability to the catheter located either proximal to or distal to the exit opening; and a visual marker element positioned on the catheter and aligned with the exit opening in the catheter, the visual marker element configured to be within a field of view captured by the imaging element and further configured to provide a visual indication of the orientation of the exit opening of the catheter with respect to an imaged vessel occlusion.
 10. The system of claim 9, wherein the imaging element includes an ultrasound transducer.
 11. The system of claim 9, wherein the imaging element comprising an array of ultrasound transducers.
 12. The system of claim 10, wherein the ultrasound transducer is rearward looking away from a distal end of the catheter body.
 13. The system of claim 9, further including a communication connector coupled to the imaging element, the communication connector extending within at least a portion of the catheter.
 14. The system of claim 13, the communication connector is embedded into a sidewall of the catheter.
 15. The system of claim 9, further including a balloon carried by the catheter. 